A hospital-acquired infection, also known as a HAI or in medical literature as a nosocomial infection, is an infection whose development is favored by a hospital environment, such as one acquired by a patient during a hospital visit or one developing among hospital staff. Such infections include fungal and bacterial infections and are aggravated by the reduced resistance of individual patients. [See “Nosocomial Infection”. A Dictionary of Nursing. Oxford Reference Online. 2008].
In the United States, the Centers for Disease Control and Prevention estimated roughly 1.7 million hospital-associated infections, from all types of microorganisms, including bacteria, combined, cause or contribute to 99,000 deaths each year. Nosocomial infections can cause severe pneumonia and infections of the urinary tract, bloodstream and other parts of the body. Many types are difficult to attack with antibiotics, and antibiotic resistance is spreading to Gram-negative bacteria that can infect people outside the hospital. [See Pollack, Andrew. “Rising Threat of Infections Unfazed by Antibiotics” New York Times, Feb. 27, 2010]. In March 2009, the CDC released a report estimating overall annual direct medical costs of healthcare-associated infections ranged from $28-45 billion. [See Scott R D. The direct medical costs of healthcare-associated infections in US hospitals and the benefits of prevention, 2008. CDC].
CRE, which stands for Carbapenem-Resistant Enterobacteriaceae, are a family of germs that are difficult to treat because they have high levels of resistance to antibiotics. Klebsiella species and Escherichia coli (E. coli) are examples of Enterobacteriaceae, a normal part of the human gut bacteria that can become carbapenem-resistant. Types of CRE are sometimes known as KPC (Klebsiella Pneumoniae Carbapenemase) and NDM (New Delhi Metallo-beta-lactamase). KPC and NDM are enzymes that break down carbapenems and make them ineffective.
Healthy people usually do not get CRE infections. In healthcare settings, CRE infections most commonly occur among patients who are receiving treatment for other conditions. Patients whose care requires devices like ventilators (breathing machines), urinary (bladder) catheters, or intravenous (vein) catheters, and patients who are taking long courses of certain antibiotics are most at risk for CRE infections. Some CRE bacteria have become resistant to most available antibiotics. Infections with these germs are very difficult to treat, and can be deadly—one report cites they can contribute to death in up to 50% of patients who become infected. [See “CDC: Action needed now to halt spread of deadly bacteria: Data show more inpatients suffering infections from bacteria resistant to all or nearly all antibiotics” (Press release). The Centers for Disease Control. Mar. 5, 2013].
Hospitals have sanitation protocols regarding uniforms, equipment sterilization, washing, and other preventive measures. Thorough hand washing and/or use of alcohol rubs by all medical personnel before and after each patient contact is one of the most effective ways to combat nosocomial infections. Despite sanitation protocol, patients cannot be entirely isolated from infectious agents. Furthermore, patients are often prescribed antibiotics and other antimicrobial drugs to help treat illness; this may increase the selection pressure for the emergence of resistant strains. [See McBryde E S, Bradley L C, Whitby M, McElwain D L (October 2004). “An investigation of contact transmission of methicillin-resistant Staphylococcus aureus”. J. Hosp. Infect. 58 (2): 104-8].
Sanitizing surfaces is an often overlooked, yet crucial, component of breaking the cycle of infection in health care environments. Modern sanitizing methods such as NAV-CO2 have been effective against gastroenteritis, MRSA, and influenza agents. Use of hydrogen peroxide vapor has been clinically proven to reduce infection rates and risk of acquisition. Hydrogen peroxide is effective against endospore-forming bacteria, such as Clostridium difficile, where alcohol has been shown to be ineffective. Ultraviolet cleaning devices may also be used to disinfect the rooms of patients infected with Clostridium difficile after discharge.
Micro-organisms are known to survive on inanimate ‘touch’ surfaces for extended periods of time. This can be especially troublesome in hospital environments where patients with immunodeficiencies are at enhanced risk for contracting nosocomial infections. Touch surfaces commonly found in hospital rooms, such as bed rails, call buttons, touch plates, chairs, door handles, light switches, grab rails, intravenous poles, dispensers (alcohol gel, paper towel, soap), dressing trolleys, and counter and table tops are known to be contaminated with Staphylococcus, MRSA (one of the most virulent strains of antibiotic-resistant bacteria) and Vancomycin-Resistant Enterococcus (VRE). Objects in closest proximity to patients have the highest levels of MRSA and VRE. This is why touch surfaces in hospital rooms can serve as sources, or reservoirs, for the spread of bacteria from the hands of healthcare workers and visitors to patients. [See Wilks, S. A., Michels, H., Keevil, C. W., 2005, The Survival of Escherichia Coli O157 on a Range of Metal Surfaces, International Journal of Food Microbiology, Vol. 105, pp. 445-454; and U.S. Department of Defense-funded clinical trials, as presented at the Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, D.C., Oct. 28, 2008].
When a patient is being treated in hospital with antibiotics, one side-effect is the increase in Clostridium difficile (C. difficile). When the bacteria are in a colon in which normal gut flora has been destroyed (usually after a broad-spectrum antibiotic such as clindamycin has been used), the gut becomes overrun with C. difficile. People are most often nosocomially infected in hospitals, nursing homes, or other medical institutions, although infection outside medical settings is increasing. C. difficile infection is a growing problem in healthcare facilities. The rate of C. difficile acquisition is estimated to be 13% in patients with hospital stays of up to two weeks, and 50% with stays longer than four weeks. [See Clabots, C. R.; Johnson, S.; Olson, M. M.; Peterson, L. R.; Gerding, D. N. (September 1992). “Acquisition of Clostridium difficile by hospitalized patients: evidence for colonized new admissions as a source of infection”. Journal of Infectious Diseases 166 (3): 561-7].
Chlorine dioxide has generated interest for control of microbiological growth. Unlike chlorine, chlorine dioxide remains a gas when dissolved in aqueous solutions and does not ionize to form weak acids. The biocidal activity of chlorine dioxide is believed to be due to its ability to penetrate bacterial cell walls and react with essential amino acids within the cell cytoplasm to disrupt cell metabolism. Unfortunately, chlorine dioxide in solution is unstable with an extremely short shelf life. Chlorine dioxide solutions must typically be generated at its point of use such as, for example, by a reaction between a metal chlorate or metal chlorite in aqueous solution and a liquid phase strong acid. However, the use of liquid phase strong acids poses handling issues and safety concerns.
In view of this, it would be desirable to develop a broad spectrum disinfectant that is safe, efficacious and fast, has no harmful byproducts, cleans and disinfects and/or sterilizes in one step, has a long shelf life, and does not cause and is not affected by pathogenic mutation.